The present invention relates generally to cellular communications and more particularly to a cellular handset with an adjustable analog to digital converter that allows the cellular handset to process wireless communications in two or more formats.
Cellular wireless communications are well known in the art. Many different standards and formats have been developed and implemented for enabling cellular wireless communications between cellular base stations and cellular handsets. For example, the advanced mobile phone service format (xe2x80x9cAMPSxe2x80x9d) was an initial analog format that was used to transmit data between a cellular base station and a cellular handset. The Global System for Mobile Communications (xe2x80x9cGSMxe2x80x9d) format is a digital format that uses a combination of time division multiple access (xe2x80x9cTDMAxe2x80x9d) and frequency division multiple access (xe2x80x9cFDMAxe2x80x9d) coding to transmit encoded data between a cellular base station and a cellular handset. Code division multiple access (xe2x80x9cCDMAxe2x80x9d) systems have also gained widespread acceptance for encoding data for transmission between a cellular base station and a cellular handset.
The large number of code and transmission formats that may be used for cellular communications has resulted in a number of different circuits that may be used to provide communication services from a cellular handset. Thus, cellular handsets are not interchangeable, and must be designed for use with one of the standardized formats for cellular data encoding and decoding. Although multi-rate phones are known in the art, such multi-rate phones suffer from various drawbacks. For example, one common drawback for multi-rate phones is that the multi-rate circuitry typically comprises redundant dual circuitry, such that both circuitries are active even though only one circuitry may be used at any given time. This configuration results in excess power consumption. Likewise, because dual sets of circuitry are used, it is necessary to construct the handset with hardware that will be idle and standing by for an unknown amount of use. This design constraint also results in a limit on the number of formats that can be processed by a given dual mode phone. For example, a dual mode phone typically would not be designed to be compatible with more than two common code and transmission formats, as this would result in a significant amount of excess equipment that would be idle at any given time.
Therefore, a cellular handset is required that can be adapted for use with multiple standard formats without requiring excess energy or excess equipment costs.
A cell phone is provided that may be used with multiple radio formats, such as GSM and CDMA. The cell phone includes a receiver that receives radio signals and converts them into electrical signals. An analog to digital converter is connected to the receiver and converts an analog input to a digital output having an adjustable number of bits at an adjustable sampling frequency. A cell phone application specific integrated circuit is connected to the analog to digital converter, which is used to process the digital output to extract encoded telecommunications data in one of the supported radio formats.
The present invention provides many important technical advantages. One important technical advantage of the present invention is an analog to digital converter that allows the sampling frequency and bit size of the sample to be adjusted in accordance with known standard formats for cellular communications. For example, the sampling frequency and bit size of samples of the present invention may be adjusted to allow processing of data and the GSM, CDMA, and other known and useful standard formats. Thus, the present invention allows a single set of cellular circuitry to perform processing of data in two or more standardized formats without requiring separate sets of the circuitry that are designed for each format to be contained within a single handset.
Another important technical advantage of the present invention is an adjustable analog to digital converter that may be readily adjusted to provide different sampling frequencies and sample bit sizes. The analog to digital converter of the present invention may include polarity of cells, where the number of cells may be adjusted as required. The cells of the analog to digital converter of the present invention may also be turned off when not being used, thus optimizing power usage by the analog to digital converter.